Dry-crushing mill



v Feb. 19 1924. v

O. A. ELLIS DRY CRUSHING MILL original Filed may 51 1918 3 sheets-Sheet 1 I Feb. 19 1924.

O. A. ELLIS DRY CRUSHING MILL original Filed May 51 191e 5 sheets-sheet 2' ,W .WN NN l JN AQ w A m H V .www .Il ll I .N Il m ii, I o @II y EN |Ik KN .li III Nm. JN

Feb. 11.9 1924.

' O. A. ELLIS DRY CRUSHING MILLy original Filedxmay 31 1918 s sheets-,sheet 5.l

Patented Feb. 19, 1924.

OSCAR ANDREW ELLIS, 0F SAN FRANCISCO, CALIFORNIA.

DRY-CRUSHING MILL.

Application nica may a1, 191s, serial T o all whom t may concern:

Be it known that I, OSCAR ANDREW ELLIS, a citizen of the United States, residing at San Francisco, in the county of San Francisco and State of California, have invented certain new and useful Improvements in Dry-Crushing Mills, of which the following is a specification.

My invention relates to crushin mills, and more particularly to mills of thls character adapted to do dry grinding.

The invention will be illustrated and described in connection with a crushing mill of the ball type, such as covered by my copending application Serial No. 195,628, although in its broaderaspects, it is by no means limited'to this type.

As is well known, ball mills are usually. operated by the wet method, that is to say, water is used to flush the grinding trough or runway and thus form the pulverized material into a kind of sludge which can then be'run oil' through pipes. Many materials, however, such as magnesite, lime, cement, etc., must, of necessity, be handled dry. It is therefore the main object of the present invention to provide improved means for removing the di?7 pulverized material from such a mill as ast as it leaves the grinding balls and to convey it to the desired point.

Another object of the invention is to provide, in connection with a mill having a freely movable saddle of the type shown in my above mentioned application, suitable means for preventing excessive lateral displacement of the saddle due to the stress of the driving belt.

In order that the invention may be readily understood, reference is had to the accompanying drawings, forming part of this specification and in which, f

Fig. 1 is a side elevation of a ball mill embodymg my invention, parts being broken awa and parts being shown in section;

Fig. 2 is a plan view thereof, parts beinl broken away;

Fig. 3 is a vertical section on the line 3--3 of Fig. 2, looking in the direction of the arrow; and,

Fig. 4 is a detailed face view, on an enlarged scale, of a cleaning brush hereinafter described.

Referring to the drawings in detail, the mill is erected on a suitable foundation 1, of concrete or the like. Set into this founda- 'tion is a vertical wall 2, which may conven- No. 237,462. ARenewed July 14, 1923.

f iently be formed of sheet metal. Inside of this and disposed somewhat above the same 1s a second, substantially circular, wall 3, which encloses the grinding chamber and balls and in which the usual screens are set. Y

4 designates the saddle which rests on a series of balls 14, adapted to roll in the annular trough or runway 13, supported on the concrete base 1.

On the upper face of the saddle 4 is an annular flange 4, and to this flange is secured the lower edge of a relatively large pulley 5. This pulley is closed at the top by a plate 6, through which extends a central feed hopper 7, having at its lower end an opening 8, which delivers into a central vertical tube or chute 9 carried by a suitable bracket 10, supported by the. saddle 4. The chute 9 extends down through the saddle and discharges the material at the center of the annular runway 13, directly over a distributmg cone 1 1. This cone is secured to the concrete base by means of a suitable anchor 12.

The usual screens 15 surround the runway 13, and the pulverized material passes through these screens.

From the upper edge of the'wall 2 to the upper part of the inner wall 3 extends a canopy or housin 16, which may be formed of sheet metal, ut is here illustrated as made of flexible material, such as canvas.

This is tightly held t0 the upper edge of the wall 2 by means of a hoop 17, which rests 1n brackets 18 and is secured in posi- `tion as by pins 19. At its upper edge the canopy 16 is secured to the wall 3 by means of a hoop 20. In order to seal the space around the outside edge of the saddle, I provide an annular hood or shield 21, secured to the upper edge of the wall 3 by means of a hoop 22. The canvas hood extends up over the edge of the wall 3 and thence inwardly and downwardly toward the saddle, where it is secured at its inner edge to another hoop 23. It will be seen that this hoop 23 is not attached to anything, but rests-lightly upon the upper surface of the saddle and is capable of loating, or moving up and down with the saddle.

Surrounding the annular rinding trqugh.

or runway 13 is a closed c amber formed partially the concrete base 1. This chamber is divided by partitions 25 into a plurality of hoppershaped compartments 24, two of such comby the canopy 16 and partially by partments being shown.V It will be seen that these'compartments have sloping or converging walls and bottoms, and at the lowest point of the bottom of each compa-rtment I provide an outlet 26, opening into a pipe 27. The pipes 27 are preferably given a slight pitch and unite to form a main discharge pipe or conduit 28. I provide some suitable means for creatina a current of air through the pipes and chambers just described. 'Ihe means shown in the drawing consists of a centrifugal fan or blower 29, which may be driven by a suitable pulley and belt 30 and 31. The discharge pipe 32 from this fan extends down into the pipe 28, as indicated at 33, in Fig. 1, and as will be well understood, the blast of air issuing from the pipe 33 has an injector action which serves to reduce the pressure in the pipes 27 and thus induce air currents therein.

It will be noted that the saddle 4 and associated parts has no fixed shaft or bearings, but is free to' move both vertically and laterally within certain limits, as fully described in my said application Serial No. 195,628. The saddle and pulley are driven by means of a power belt 34, engaging the pulley 5, and While in my above mentioned prior application, the saddle was entirely unrestrained, I have observed in practice that with such an arrangement the stress of the driving belt sometimes tends to pull the saddle oil' center. I have therefore found it desirable to devise some means for overcoming this tendency. As shown in the drawings, I have provided an anchor belt 35 for this purpose. This belt also works over the pulley 5 and paes around a fixed idler 36, journaled in a bracket 37, secured to a post 38, or other Suitable support. Such anchor belt, while allowing the freedom of movement necesasry to successful operation, resists the pull of the driving belt, and pref vents undue lateral displacement of the sade. f In order to keep the screens 15 clean and open, I preferably provide one or more brushes 39. These brushes are secured to the edge of the saddle 4 and revolve therewith. Each brush is supported by means of a shank 40, which is hinged at 41 to a bracket 42, secured to the saddle. A resilient wire spring 43 is bent around the hlnge and passes under the shank 40 in such a way as to urge the brush 39 outwardly against. the screens 15, as will be apparent. The operationof my improved dry mill will now be readily understood.l The material to be ground is fed in through the hopper 7 and chute 9, whence it is delivered on to the cone 11v and passes therefrom to the annular trough under the balls. It will be seen that all parts of the mill are enclosed practically air-tight, the only opening being at the bottom of the hopper 7. When Leashes therefore the fan 29 is put in operation, a strong current of air will be caunsed to flow down through the hopper 7 and chute 9 out over the trough 13 and throu h the screens 15, thus forcing the dry pulverlzed material to pass through such screens into the compartments 24. From thence the material is carried by the air currents through the pipes 27 and 28 to any desired point.

It will thus be seen that I have provided simple but ellicient pneumatic means for carrying away the dry pulverized material from a crushing mill, and it is thought that the many advantages of my invention will be obvious to those skilled in the art.

What I claim is:

1. In a crushing mill, the combination with a circular grinding device, of a closed annular chamber surrounding said device and extending below the same, means for feeding material to be ground into the center of the grinding device, and means connected with the bottom of said annular chamber forl reducing the air pressure therein so as to cause the dry pulverized material from the grinding device to flow into and through such chamber.

2. In a crushing mill, the combination with anr annular trough, grinding balls adapted to run in said trough, a saddle overlying said balls, a feed chute at the center of said saddle, a chamber surrounding and extending below the trough and balls, and means for reducing the air pressure in said chamber so as to cause a current of air to flow downwardly through said feed chute and over said annular trough so as to carry lthe dry pulverized material into said cham- 3. In a crushing mill, the combination with a casing of an annular trough enclosed therein, of balls adapted to run in said trough, a saddle overlying said balls and forming an air-tight partition, an open feed chute extending through said saddle, means for preventing the entrance of air between the casing and the edge of said saddle, a closed chamber surrounding said annular trough and casing, and means for causing a current of air to How into said feed chute, across said annular trough and into and through said chamber so as to carry away the dry pulverized material.

4. In a crushing mill, the combination with an annular trough and balls running therein, of a saddle overlying androtating p with said balls, said saddle having an opening near the center thereof, a closed chamber surrounding said annular trough, means for reducing the pressure in said chamber so as to cause air to flow throu h the opening in the saddle, over the annuIar trough and into and through said chamber, and means for preventing the entrance of air around the edge of said saddle, such means comkprising an annular exible hood having at 1ts inner edge a floating hoop adapte to rest on the saddle.

Y 5. In a crushing mill, the combination with'a circular grindingdevice having rotatin parts, of screens surrounding said grin ing device, means for causing a-current of air to flow outwardly through said grinding device and screens, to carry away terial to be ground into the center of said trough, a closed chamber surrounding said trough and divided into a plurality of hopper-shaped compartments extending below such trough, each of said compartments having `a sloping bottom, a pipe tapping the lowest point of the bottom of each compartment, and means for creating a current'l of air through said pipes so as to carry away the dry pulverzedV material from the annular crushing trough.

- 7. In a ball mill, the combination with an annular trou h and balls, of a saddle overlying the ba ls and free to move laterall thereon, a belt pulley secured to said sadd e, a wer belt running around said pulley, an means independent ofthe trough and balls for preventino' undue lateral shi ting of the ulley an saddleY due to the stress of sai belt. Y l

8. In a ball mill, the combination with an annular trou h and "balls, of" a ,saddle overlying the ba ls and free to move both vertically and laterally relative to the trough, means for rotating said saddle com.-`

prising a power wheel carried by the saddle, is l and 'restraining means engagingsaid wheel for preventing undue lateral displacement" of the wheel and saddle. 4

9. In a ball mill, the combination with an annular trough and balls, of a saddle overl ing the balls and free to move laterally t ereon, a belt pulley secured to said saddle, a power belt vrunning around said pulley, an anchor belt also working over said pulley,

and a fixed idler aroundwhich said anchor belt passes.

In testimony whereof I aix my signature.

OSCAR ANDREW ELLIS. 

